The present invention relates to seating units having a seat support and back coupled to a base for synchronous movement and having an underseat control for controlling movement of the back to recline positions.
Synchrotilt chairs provide a seat that moves simultaneously with recline of its back, such as to reduce “shirt pull” upon recline, to improve comfort, and to promote healthier support when performing tasks while seated for extended periods of time. In one type of synchrotilt chair, the seat moves forward upon recline of its back, so that a seated user's hands stay relatively stationary whether the back is in the upright or reclined position. This is not easily accomplished, since it requires a mechanism that creates stable and smooth forward movement of the seat during rearward recline of the back. Also, it is desirable to reduce cost, weight, and assembly time, and to accomplish this with simplified components. At the same time, the competitive furniture market requires high quality and durability. There are many conflicting and challenging design requirements, such as the desire for small package size, while maintaining an attractive appearance, an environmental “green” friendliness (including the ability to separate components into recyclable parts without substantial effort), and a desire for design flexibility, relatively few components, and mechanically-efficient arrangements that are durable, long-lasting, robust, and easily assembled.
It is known to limit rearward recline of a back through use of a pivoting cam. (See cam/back-stop mechanism 36 in FIG. 8 of Bedford U.S. Pat. No. 5,871,258.) However, it is desirable to provide alternative motions and parts to meet packaging requirements and functional requirements of the present chair design with novel biasing springs. Also, improvements are desired to increase design flexibility, simplify components, reduce parts and pieces, make them lower in weight and cost, improve assembly and reduce manual labor during assembly, and to make the assembly more durable and robust.
Thus, a system having the aforementioned advantages and solving the aforementioned problems is desired.